Edit this line like this:
$this->output('<input type="text" ' .'placeholder="Enter here" ' . $search['field_tags'] . ' value="' . @$search['value'] . '" class="qa-search-field"/>');
Note this actually applies to SnowFlat. For some reason the theme is hardcoding three dots at the end of the text so you have to modify the theme if you don't want them.